With the increase in cracking severity of FCC and the rise of hydroprocessing, the problem of processing byproduct n-pentane has become more significant. Some refineries isomerize the low 62 RON (research octane number) n-pentane to isopentane (RON=92). Isomerization of the n-pentane to isopentane leads, however, to an increase in gasoline volatility (RVP of n-pentane=15 6; RVP of isopentane=20.4); and environmental factors may limit the amount of isopentane usable in gasoline in the future.
Cyclopentane offers several advantages over both n-pentane and isopentane as a gasoline additive. Its research octane number is even higher than that of isopentane, and its volatility is substantially lower, as shown below:
______________________________________ Compound RON MON RVP ______________________________________ n-pentane 61.7 62.6 15.6 isopentane 92.3 90.3 20.4 cyclopentane 101.3 84.9 9.9 ______________________________________
Compared to pentane isomerization, cyclopentane production, in accordance with the invention, yields a higher octane product and at the same time reduces the RVP of the pentane fraction.